Vitiligo is a dermatologic disorder in which melanocytes are destroyed, but the mechanism of destruction and what leads to it is unknown. Among the many theories proposed for the pathogenesis of this disease is that it is an autoimmune phenomenon. This theory is supported by the discovery of autoantibodies to melanocytes and other pigment cell antigens. This autoantibody is lytic for melanocytes in titers that are highest during the active state of the patients including immunoprecipitation, modified ELISA, ADCC, europium release assay, and more recently a fluorescent antibody technique, utilizing flow cytometry. The specific aims are: l) to screen the sera of vitiligo patients and control subjects by flow cytometry for autoantibodies to melanocytes and other selected cell lines; 2) to secure blood from patients positive for autoantibody and from negative controls and stimulate their lymphocytes with melanocytes; in vitiligo. Vitiligo patients involved in this study will be examined and followed up in the outpatient facilities of the General Clinical Research Center. Flow cytometry resources will also be fully utilized in this investigation.